Lufthansa and Turkish Airlines Both Stall My Missing Flight Miles

On my Lufthansa flight from Frankfurt to Mexico City, even though I provided my Turkish Airlines Miles & Smiles number as my frequent flyer program, the miles for my outbound flight were never credited to my account. The miles for my return flight, purchased under the same booking code, were credited to my Miles & Smiles account without any issue — the fact that only the outbound flight is missing suggests this stems from a systemic processing error.
After reporting the missing miles, I was informed that the miles for that outbound flight had mistakenly been credited to my Lufthansa Miles & More account instead. When I raised this with Lufthansa, my objection was accepted, the miles for that flight were completely removed from my Miles & More account, and Lufthansa confirmed this action to me in writing. Lufthansa also told me that I needed to contact Turkish Airlines to have these flight miles transferred to my Miles & Smiles account.
Even though my boarding pass is on file in the system, and even though I forwarded Lufthansa's written email — confirming both the mile removal and their approval — to Turkish Airlines through the Miles & Smiles channel, I keep getting only the response "waiting for confirmation from Lufthansa," with no progress being made and no concrete action taken.
It appears there are numerous similar complaints about Miles & Smiles miles being missing or incorrectly credited on flights operated by Star Alliance member airlines. This suggests the issue isn't an isolated glitch, but rather a recurring process failure that's harming passengers repeatedly.
As a passenger, I've been caught in the middle between two Star Alliance member airlines throughout this process. I'd appreciate it if the missing miles for this flight could be credited to my Miles & Smiles account as soon as possible, with the necessary partner confirmations completed, and if this process could be managed more efficiently and transparently going forward to prevent similar situations for other passengers.